1. Field of the Invention
The present invention relates to a sampling device for taking sterile samples and more particularly, to a sampling apparatus for removably attaching sample collecting containers to withdraw uncontaminated samples from a sampling media.
2. Description of the Related Art
Sterile sampling of fluids is performed periodically in many industries by removing a small fluid sample from a large batch or a continuous process into a sample collecting bottle for analysis. Such sterile sampling may include, for example, monitoring biological activity in fermenters, testing liquid foods in the food processing industry, and monitoring water quality in water treatment plants.
Monitoring of biological activity in a fermenter is generally conducted by taking samples of the biological media within the fermenter at regular intervals over a period of time. For some processes it may be necessary to take such samples as often as about every fifteen minutes for monitoring of the process. Open sampling in which a liquid sample is drained into an uncovered sample bottle creates undesirable aerosols.
An example of a known biological sampling apparatus for connection to a fermenter which reduces aerosol generation is illustrated in FIG. 1. According to the known assembly, an outlet of the fermenter is connected to an outlet assembly 10 of the sample taking apparatus. Connected to the outlet assembly 10 is a sampling assembly 12 including a sample collecting bottle 14. The sampling assembly 12 is also removably connected to a steam trap assembly 16.
The known sampling assembly 12 includes the bottle 14 having a cap 18, an inlet tube 20, and a vent 22 extending through the cap 18 with a filter provided in the vent. Connected to the inlet tube 20 is a valve 24 for directing fluid to the bottle 14 and steam to the steam trap 36. The sampling assembly 12 has a first connection end 26 for a connection by a tri-clamp 28 to an end 38 of the outlet assembly 10 and a second connection end 30 shown connected by a second tri-clamp 32 to the steam trap assembly 16.
In order to take a sample with the known sample taking apparatus of FIG. 1, the sampling assembly 12 including the bottle 14, the valve 24, and the two connection ends 26, 30 is autoclaved prior to use. This sampling assembly 12 is then connected to the outlet assembly 10 of the fermenter and to the steam trap assembly 16 by the tri-clamps 28, 32. Once the sampling assembly 12 has been attached by the tri-clamps 28, 32, steam is passed from a steam inlet 34 to the sampling assembly 12 and through a portion of the sampling assembly into a steam trap 36. This steam sterilization process is conducted for about fifteen to twenty minutes to sterilize the inlet pipe and valve 24 of the sampling assembly 12. After this steam sterilization step, a biological sample is withdrawn from the fermenter through the outlet assembly 10 and sampling assembly 12 into the bottle 14. Air escapes through the vent 22 during sampling collection. The sampling assembly 12, including the bottle 14, cap 18, and valve 24 are then disconnected by the tri-clamps 28, 32 from the fermenter and the steam trap 36 and a new sampling assembly 12 may be attached for withdrawal of a subsequent sample.
The drawbacks of this known sample taking system are the requirement that the entire bottle 14, cap 18, and valve 24 combination be autoclaved before use and that this entire assembly must be replaced for each sample taken. In addition, the known system does not provide the ability to cool the sampling assembly after the heating caused by the steam sterilization step. It would be desirable to provide a sampling device which is more easily attached and detached from a fermenter for taking samples, which does not require that an entire assembly including a bottle, a cap, and a valve be used for each sampling occurrence and which allows cooling.